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Biomedical subjects

S Yoshihara

Publications and source records attributed to S Yoshihara.

At least 19 recordsLinked to original sources

Association of epithelial damage and signs of neutrophil mobilization in the airways during acute exacerbations of paediatric asthma.

We examined whether epithelial damage is associated with mobilization of neutrophils or eosinophils in the airway lumen during acute exacerbations of paediatric asthma. Aspirated sputum samples were harvested from 65 paediatric patients (mean age 3.4 +/- 0.4 years) during acute exacerbations of asthma. Patients with signs of infection were excluded. The presence of conglomerates of epithelial cells (i.e. "Creola bodies") in the aspirated sputum was utilized as a marker of epithelial damage. Among the paediatric asthma patients, 60% displayed Creola bodies (CrB+: n = 39) in their sputum samples whereas the remaining patients did not (CrB-: n = 26). CrB+ patients displayed more than a 20-fold increase in the concentration of the neutrophil-mobilizing cytokine interleukin (IL)-8 (pg/ml) and of the neutrophil product neutrophil elastase (NE, g/l), respectively, compared with CrB- patients (IL-8: 7468.2 +/- 1953.6 versus 347.9 +/- 72.6, P < 0.01; NE: 2072.4 +/- 419.0 versus 438.5 +/- 125.7, P < 0.01). Even though not statistically significant, a corresponding trend was observed for the relative number of sputum neutrophils. In contrast, the concentration of the eosinophil-mobilizing cytokine IL-5 and the esoinophil product ECP tended to be lower in CrB+ than in CrB- patients (P > 0.05). In conclusion, as indicated by the analysis of aspirated sputum, epithelial damage is associated with a locally enhanced chemotactic signal for and activity of neutrophils, but not eosinophils, during acute exacerbations of paediatric asthma. It remains to be determined whether these indirect signs of neutrophil mobilization in the airway lumen mirror an increased number of neutrophils in the surrounding airway tissue.

Acute Disease↗

Lower incidence of Bronchiolitis obliterans in allogeneic hematopoietic stem cell transplantation with reduced-intensity conditioning compared with myeloablative conditioning.

Bronchiolitis obliterans (BO) is one of the most devastating complications after allogeneic stem cell transplantation (HSCT). However, its true pathogenesis is still to be elucidated. We conducted this study to find whether tissue damage due to high-dose chemo-radiotherapy is related to its pathogenesis. In all, 144 patients who received allogeneic HSCT between May 1999 and October 2001, and survived more than 80 days after transplant, were analyzed. Clinical course, pulmonary function tests, imaging studies including CT scan, and pathology results were reviewed. The overall incidence of BO was 9.7% (14/144). The cumulative incidence of BO at 2 years after transplant was 17% with myeloablative conditioning, and 2.3% with reduced intensity conditioning (P=0.024). Multivariate analysis showed that myeloablative conditioning was the only factor which affected the incidence of BO. Development of BO did not significantly affect the overall survival of patients. However, if they developed BO earlier than 200 days post transplant, the prognosis was significantly worse than if they developed it later than 200 days post transplant (P=0.003) or if they did not develop BO (P=0.002). Our results imply that tissue damage secondary to intensive chemo-radiotherapy may contribute to the pathogenesis of BO.

Adolescent↗

Th1-biased humoral immune responses against Wilms tumor gene WT1 product in the patients with hematopoietic malignancies.

The Wilms' tumor gene WT1 is highly expressed in leukemias and myelodysplastic syndrome (MDS), and WT1 expression levels increase along with the disease progression in chronic myeloid leukemia and MDS. We previously reported that IgM and IgG WT1 antibodies were detected with significantly higher detection rate and antibody titers in leukemias and MDS compared to those in healthy volunteers. In this study, whether IgG humoral immune responses against WT1 protein were Th1- or Th2-type were determined by measurement of four subclasses of IgG WT1 antibody, IgG1, IgG2, IgG3, and IgG4. In leukemias and MDS, Th1-type WT1 antibodies such as IgG1, IgG2, and IgG3 were significantly increased in both detection rate and antibody titers compared to those in healthy volunteers, whereas Th2-type WT1 antibody such as IgG4 did not increase. These results showed that Th1-biased humoral immune responses against WT1 protein were generated in leukemias and MDS. These results should allow us to consider that Th1-biased cellular immune responses against WT1 protein, which was essentially needed for cancer immunotherapy targeting WT1, should be elicited in patients with hematopoietic malignancies.

Antibody Formation↗

Hepatic vein anastomotic stricture after living donor liver transplantation.

This report discusses the pathophysiology of and therapeutic methods to address hepatic vein anastomotic stricture after living donor liver transplantation (LDLT). From 1994 to 2002, our 15 LDLTs using the lateral segments or left lobes included four recipients who experienced 28 occurrences of this complication after the operation. The period between LDLT and the first stricture was 4.0 +/- 1.2 months. The age of the affected recipients (31.0 +/- 8.2 years) was significantly higher than that of the nonaffected patients (7.0 +/- 4.1 years, P < .05). Graft liver/standard liver volume ratio was 39.1% +/- 3.8% in the former and 77.9% +/- 12.7% in the latter cases (P < .05). Initial symptoms of stricture were ascites (42.9%), abdominal distention (42.9%), liver enzyme elevation (10.7%), and gastrointestinal bleeding (3.6%). In addition, 14 of 28 stricture cases (50%) showed increased blood trough levels of tacrolimus. Doppler ultrasonography was used for diagnosis, and balloon dilatations performed in all stricture patients, thereby hepatic significantly reducing venous blood pressure from 33.5 +/- 1.7 to 20.3 +/- 1.5 cmH2O. All patients finally resolved the strictures after several treatments. The stricture after LDLT was associated with small-for-size grafts, suggesting that liver regeneration may lead to anatomical changes and strictures. Since tacrolimus is metabolized by the liver, its blood trough level is one initial symptoms of stricture. Balloon dilatation was useful and safe as the treatment, while problems have been reported after stent insertion in the hepatic vein.

Adult↗

Hepatic clearance improves after angioplasty of the hepatic vein.

Anastomotic stricture sometimes causes hepatic congestion leading to decreased hepatic clearance of drugs. We herein describe a correlation between trough levels of tacrolimus and an anastomotic stricture of the hepatic vein. A 13-year-old boy underwent living donor liver transplant with a left lobe graft from his mother. Outflow blockage due to an anastomotic stricture of the hepatic vein developed 3 months after transplant. His anastomotic site had been repeatedly treated with percutaneous transvenous angioplasty (PTA) by balloon dilation. About 1 year after transplant, his trough level of tacrolimus promptly decreased after balloon dilation (from 15.7 to 5.6 ng/dL). Liver function tests showed abnormalities, which were diagnosed as acute cellular rejection, and he was treated with pulse steroid therapy. The calculated half-life of tacrolimus (T1/2) showed marked improvement after PTA (from 35 to 22 hours). A 45-year-old woman underwent living donor transplantation due to alcoholic liver cirrhosis with a left lobe graft from her brother. An anastomotic stricture of the hepatic vein developed 4 months after transplant. She was treated with balloon dilation, which caused an abrupt decrease in the trough level of tacrolimus (12 to 4 ng/dL). Her alkaline phosphatase was elevated and she was diagnosed with rejection, which was treated with an increase of dosage of tacrolimus. In outflow block, the T1/2 of tacrolimus increases probably due to decreased hepatic clearance by stagnation or congestion of the liver. However, hepatic clearance of drugs quickly recovers after PTA. Close monitoring of immunosuppressive agents is fundamental at the time of angioplasty to avoid acute cellular rejection as developed in our two cases.

Adolescent↗

Efficacy of cutting balloon for anastomotic stricture of the hepatic vein.

Anastomotic stricture of the hepatic vein is an annoying complication, especially in living donor liver transplantation. Balloon dilation has been utilized but is sometimes associated with recurrences. Recently, a cutting balloon was invented for treatment of arteriosclerosis. Herein we report the results of application of this device for treatment of anastomotic strictures of the hepatic vein in two living donor liver transplant recipients who underwent percutaneous dilation of the hepatic vein with a cutting balloon (8 x 10 mm, Atherotome, Boston Scientific). Case 1, a 26-year-old woman transplanted for subacute fulminant hepatitis, had been treated for an anastomotic stricture by balloon dilation on 15 occasions over a 2- to 3-month interval. Case 2, a 13-year-old boy transplanted for cryptogenic liver cirrhosis, had been treated for an anastomotic stricture by balloon dilation biannually. The cutting balloon was applied safely without severe complications. The first case showed a recurrent anastomotic stricture at 6 months after dilation. Follow-up at 6 months in the second case revealed a mild recurrence of the stricture. Anastomotic stricture of the hepatic vein jeopardizes the graft and the recipient. The reported treatments involve venoplastic surgery and expandable metallic stents. Application of a cutting balloon seemed to be a safe, convenient modality. However, its effect was not indefinite, so a cutting balloon of greater diameter or application of an expandable metallic stent may be considered for patients with multiple recurrences of their anastomotic stricture.

Adolescent↗

Preferential expression of the vasoactive intestinal peptide (VIP) receptor VPAC1 in human cord blood-derived CD34+CD38- cells: possible role of VIP as a growth-promoting factor for hematopoietic stem/progenitor cells.

Primitive hematopoietic progenitor cells such as severe combined immunodeficiency- repopulating cells and long-term culture-initiating cells are enriched in CD34+CD38- cells derived from various stem cell sources. In this study, to elucidate the features of such primitive cells at the molecular level, we tried to isolate genes that were preferentially expressed in umbilical cord blood (CB)-derived CD34+CD38- cells by subtractive hybridization. The gene for VPAC1 receptor, a receptor for the neuropeptide vasoactive intestinal peptide (VIP), was thereby isolated and it was shown that this gene was expressed in both CD34+CD38- and CD34+CD38+ CB cells and that the expression levels were higher in CD34+CD38- CB cells. Next, we assessed the effects of VIP on the proliferation of CD34+ CB cells using in vitro culture systems. In serum-free single-cell suspension culture, VIP enhanced clonal growth of CD34+ CB cells in synergy with FLT3 ligand (FL), stem cell factor (SCF), and thrombopoietin (TPO). In serum-free clonogenic assays, VIP promoted myeloid (colony-forming unit-granulocyte/macrophage (CFU-GM)) and mixed (CFU-Mix) colony formations. Furthermore, in Dexter-type long-term cultures, VIP increased colony-forming cells at week 5 of culture. These results suggest that VIP functions as a growth-promoting factor of CB-derived hematopoetic progenitor cells.

ADP-ribosyl Cyclase↗

Lesions in the liver of guinea-pigs infected with the swine lungworm, Metastrongylus apri.

Clear spot lesions were formed on the liver surface in guinea-pigs repeatedly infected with swine lungworm, Metastrongylus apri. The largest lesion, measuring 0.25 cm in diameter, was hard and yellow and showed a large granuloma in the lobule. The nematode larva was located at the centre of the lesion. This finding is likely to be an example of erratic parasitism in guinea-pigs with metastrongylidiasis.

Animals↗

High complete response rate after allogeneic hematopoietic stem cell transplantation with reduced-intensity conditioning regimens in advanced malignant lymphoma.

The possible advantage of allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a graft-versus-lymphoma effect. We explored the feasibility and efficacy of allo-HSCT with reduced-intensity (RI) regimens in advanced malignant lymphoma (ML). A total of 20 patients with indolent (n=9) or aggressive lymphoma (n=11) received allo-HSCT with an RI regimen (RIST). The preparative regimen consisted of a combination of purine analog and alkylating agent with or without antithymocyte globulin. A total of 11 patients had chemorefractory disease, seven had chemosensitive relapsed disease and two had residual disease. All of the patients received G-CSF-mobilized blood stem cells from HLA-matched siblings. Of the 20 patients, 19 achieved engraftment with acceptable regimen-related toxicities. Seven patients developed grade II-IV acute GVHD and 15 developed chronic GVHD. Of the 15 patients with evaluable disease, 12 achieved a complete response. One died of invasive fusariosis, four subsequently died of GVHD complicated with fungal infection and one died of progressive disease. With a median follow-up of 358 days, the Kaplan-Meier estimates for 1-year overall and progression-free survival were both 70%. The high response rate with low relapse observed in this study suggests that RIST may be an effective alternative curative treatment for patients with advanced ML.

Adult↗

Characterization of genes encoding multi-domain proteins in the genome of the filamentous nitrogen-fixing Cyanobacterium anabaena sp. strain PCC 7120.

Computational analysis of gene structures in the genome of Anabaena sp. PCC 7120 revealed the presence of a large number of genes encoding proteins with multiple functional domains. This was most evident in the genes for signal transduction pathway and the related systems. Comparison of the putative amino acid sequences of the gene products with those in the Pfam database indicated that and PAS domains which may be involved in signal recognition were extremely abundant in Anabaena: 87 GAF domains in 62 ORFs and 140 PAS domains in 59 ORFs. As for the two-component signal transduction system, 73, 53, and 77 genes for simple sensory His kinases, hybrid His kinases and simple response regulators, respectively, many of which contained additional domains of diverse functions, were presumptively assigned. A total of 52 ORFs encoding putative Hanks-type Ser/Thr protein kinases with various domains such as WD-repeat, GAF and His kinase domains, as well as genes for presumptive protein phosphatases, were also identified. In addition, genes for putative transcription factors and for proteins in the cAMP signal transduction system harbored complex gene structures with multiple domains.

Bacterial Proteins↗

Mutational analysis of genes involved in pilus structure, motility and transformation competency in the unicellular motile cyanobacterium Synechocystis sp. PCC 6803.

The relevance of pilus-related genes to motility, pilus structure on the cell surface and competency of natural transformation was studied by gene disruption analysis in the unicellular motile cyanobacterium Synechocystis: sp. PCC 6803. The genes disrupted in this study were chosen as related to the pil genes for biogenesis of the type IV pili in a Gram-negative bacterium Pseudomonas aeruginosa. It was found that motility of Synechocystis cells was lost in the mutants of slr0063, slr1274, slr1275, slr1276, slr1277 and sll1694 together with a simultaneous loss of the thick pili on the cell surface. Competency of the natural transformation was lost in the mutants listed above and slr0197-disruptant. The gene slr0197 was previously predicted as a competence gene by a search with sequence-independent DNA-binding structure [Yura et al. (1999) DNA Res. 6: 75]. It was suggested that both DNA uptake for natural transformation and motility are mediated by a specific type IV-like pilus structure, while a putative DNA-binding protein encoded by slr0197 is additionally required for the DNA uptake. Based on the homology with the pil genes in P: aeruginosa, slr0063, slr1274, slr1275, slr1276, slr1277 and sll1694 were designated pilB1, pilM, pilN, pilO, pilQ and pilA1, respectively. The gene slr0197 was designated comA.

Amino Acid Sequence↗

Metabolic activation of bisphenol A by rat liver S9 fraction.

Bisphenol A (BPA) is a well-known endocrine-disrupting chemical found in the environment. To assess the metabolic modulation of estrogenic activity of BPA after ingestion, we investigated whether the incubation of BPA with rat liver S9 fraction results in metabolic activation or inactivation of estrogenic activity using a recombinant yeast expressing human estrogen receptor and MCF-7 transfected firefly luciferase plasmid for a reporter assay. When 0.1 mM BPA was incubated with rat liver S9 for 1 h, the estrogenic activity was increased about two to five times compared with that of the control, in which the S9 was inactivated prior to incubation. This metabolic activation was inhibited by SKF 525-A, an inhibitor of cytochrome P450. With increasing incubation time, the estrogenic activity increased time-dependently. Interestingly, however, the metabolic activation did not proceed with either microsomes or cytosol alone and was restored by a recombination of both fractions. The active metabolite was eluted at later retention time than that of BPA on HPLC with a reversed-phase column. Bisphenol B and methoxychlor were also activated by incubation with rat liver S9, whereas 4-tert-octylphenol and 4-nonylphenol, as well as 17beta-estradiol, were metabolically inactivated. The present results clearly indicate that BPA is metabolically activated in terms of estrogenicity under the conditions existing only with combined rat liver microsomes and cytosol.

Animals↗

Revascularization of the artery of the ligamentum teres in Perthes disease.

To study revascularization of the artery of the ligamentum teres in Perthes disease, superselective angiography was done in 22 hips. Normal appearance of the artery of the ligamentum teres was observed in two hips, both of which were of Catterall Group II in the healing stage. Thirteen hips of Catterall Group III or IV with collapse (initial stage in nine hips, fragmentation in two hips, healing in two hips) were free from apparent subluxation; however, their epiphyses were not vascularized to the medial margin. Seven hips with apparent subluxation of Catterall Group III or IV (fragmentation stage in three hips, healing in four hips) had extensive vascularized medial viable segments consisting of newly formed small arteries. Penetration of revascularization from the artery of the ligamentum teres was inhibited by collapse initially at the medial margin of the epiphysis. Revascularization consisted of newly formed small arteries that penetrated the medial area of the epiphysis after subluxation. After completion of healing, blood supply from the artery of the ligamentum teres was not important for nourishment of the capital femoral epiphysis. The authors conclude that normal vascular anatomy of the artery of the ligamentum teres is not related to the onset of Perthes disease.

Adolescent↗

Changes in glycosaminoglycan, galactosyltransferase-I, and sialyltransferase during rat liver regeneration.

After partial hepatectomy, the liver is capable of complete restoration to its normal size. The extracellular matrix, which surrounds the cells, plays important roles in this regeneration. Glycosaminoglycans (GAGs), which are components of the extracellular matrix, interact with several other matrix components and growth factors, and are involved in hepatocyte growth. In this study, the content of heparan sulfate, a major GAG in rat liver, reached a minimum at 12 hours after partial hepatectomy. Galactosyltransferase-I activity, related to the synthesis of GAGs, and sialyltransferase activity, related to the synthesis of glycoconjugates, reached a minimum at 6 hours. The serum and liver contents of hyaluronic acid reached a maximum at 1 day and returned gradually to their preoperative levels. These results suggest that polysaccharide synthesis was decreased in the Golgi apparatus of hepatocytes at the beginning of regeneration, and that hyaluronic acid degradation decreased in the lysosomes of hepatocytes. The ability to synthesize polysaccharides recovered ahead of the ability to degrade hyaluronic acid. The changes in these GAGs with time in the early regeneration period might play an important role in organ regeneration.

Animals↗

Xanthogranulomatous cholecystitis mimicking gallbladder cancer: report of a case.

A 61-year-old woman was admitted to our hospital with abnormal findings of abdominal computed tomography. Whereas she had neither fever nor abdominal pain, a cholecystitis was suspected. Ultrasonography showed a mass in the gallbladder with several stones, and an unclear border between the gallbladder and liver. Computed tomography showed a large-mass in the gallbladder with findings that seemed to indicate hepatic invasion and para-aortic lymph node metastasis. On the basis of these findings, we made a diagnosis of gallbladder cancer associated with hepatic invasion and lymph node metastasis. We treated this gallbladder tumor by hepatic arterial infusion chemotherapy via catheter with cisplatin and 5-fluorouracil. Four weeks after administration of the anti-cancer drugs, the tumorous lesion of the gallbladder could not be detected by abdominal imagings, and the gallbladder wall revealed no irregular findings. During laparotomy, the gallbladder showed signs of chronic cholecystitis, and a cholecystectomy was performed. Findings of the resected specimens showed severe inflammation, fibrosis, and bleeding in the gallbladder wall with infiltration by many foamy cells. Histopathological diagnosis was xanthogranulomatous cholecystitis. We report here a case of xanthogranulomatous cholecystitis mimicking gallbladder cancer and review the literature.

Cholecystitis↗

Long-term follow-up study of bioactive bone cement for repairing a segmental defect in a canine femur.

We report on a 7-year long-term follow-up study of a bioactive bone cement (BA cement) that was used to repair a segmental defect in a canine femur. Bilateral femoral segmental defects were repaired with metallic implants that were fixed to the femur using two kinds of bone cement. The BA cement used in this study consists of an apatite- and wollastonite-containing glass ceramic (AW-GC) with a bis-phenol-alpha-glycidyl methacrylate (bis-GMA)-based resin. The bone-cement interface was examined histologically. Previous short-term studies have shown that using BA cement for segmental replacement of the canine femur produced excellent biomechanical and histological results. The BA cement maintained the fixation of a metallic implant to the femur very well. In contrast, the PMMA cement did not maintain alignment under long-term weight-bearing conditions. The results of histological examinations showed direct bonding between the BA cement and bone, while an intervening soft tissue layer was observed at the bone-cement interface with the PMMA cement. The BA cement bonded to the bone through a Ca-P-rich reactive layer, which was twice as thick after 7 years than it was at 26 weeks. No adverse effects of BA cement were observed during the 7-year observation period.

Animals↗

Cloning and characterisation of a peroxiredoxin from the swine roundworm Ascaris suum.

Antioxidant enzymes in parasites play an important role in protection against the oxygen radicals by generating during aerobic metabolism, as well as in defence against host immune cell assault. Here we report the cloning and characterisation of a cDNA encoding peroxiredoxin from Ascaris suum (AsPrx). AsPrx is 776bp long and contains the nematode 22bp splice leader sequence at the 5' end and polyadenylation signal followed by poly(A) tail at the 3' end. AsPrx codes a full-length protein with a predicted molecular mass of 22. 6kDa, and possesses two cysteine residues at amino acid 49 and 168 that are conserved among Prx proteins. GenBank() analysis showed that the deduced amino acid sequence had significant similarity to parasite and mammalian Prx at the amino acid level. DNA nicking revealed that Escherichia coli-expressed recombinant AsPrx (rAsPrx) is enzymatically inhibited to form oxidative-nicking of supercoiled plasmid DNA. Two-dimensional immunoblot analysis with mouse anti-rAsPrx serum reacted two major constituent protein spots in extracts of adult female worms, suggesting that the native AsPrx might be function as a major antioxidant enzyme in Ascaris suum.

Amino Acid Sequence↗